Vertical and horizontal midfacial zygomaticomaxillary buttresses: 1 nasomaxillary buttress, 2 zygomaticomaxillary buttress, 3 pterygomaxillary buttress, 4 fronto-ethmoid-vomerine buttress, 5 frontal buttress, 6 infraorbital buttress, 7 inferior (U-shaped) buttress (Materials from www.aofoundation.org were used for this illustration)
Several soft tissue structures are tightly connected with the maxilla and are often affected in patients with maxillary fractures:
The infraorbital nerve
Branches of the maxillary artery supplying the midface
Orbital contents (the globe, the optic nerve, the extraocular muscles, and the lacrimal apparatus)
Since the maxilla is adjacent to the oral and nasal cavities, the orbit, and other anatomical structures, it is extremely significant both morphologically and functionally. Maxillary fractures are justly regarded as the most severe injuries.
7.1 Epidemiology of Maxillary Fractures
Maxillary fractures comprise 6–28 % of all facial fractures. Most of them occur in 20–40-year-old men; half of those acquire the trauma while intoxicated with alcohol [1–5]. Motor vehicle accidents, assaults, and falls are the major reasons for maxillary fractures [1, 3, 6, 7]. The percentage of maxillary fractures and the involvement of orbital bones secondary to motor vehicle accidents has significantly risen over the past several decades from 10 % in the 1950s to 50 % in the 1990s . Furthermore, maxillary fractures affect the zygomatic bone in 80 % of patients . The anterior visual pathway is affected to some extent in 90 % of patients, while severe damage such as globe rupture or optic neuropathy is observed in 12–20 % of cases [1, 10].
7.2 Fracture Classification
The classification of non-gunshot maxillary fractures was proposed by French surgeon René Le Fort in 1901 . Three main types of maxillary fractures have been described in experimental studies using cadaver skulls. The formation of a certain type of fracture depends on the degree, direction, and the point to which the vector force of the trauma is exerted.
Le Fort I fractures (also known as horizontal, floating, or Guérin’s fractures) are formed when the vector force of the trauma moves downward and affects the maxillary alveolar process. The fracture line extends from the nasal septum toward the edges of the piriform aperture, runs posteriorly in the horizontal direction over the apex of the teeth above the level of the bottom of the maxillary sinus, crosses the zygomaticoalveolar crest, and passes through the tuber maxillae and the lower third of the pterygoid process of sphenoidal bone (Fig. 7.2a, b). Sometimes the fracture line stops near the sockets of the second or third molar teeth. It is accompanied by transverse fracture of the nasal septum. The floor of the nasal cavity and maxillary sinus is detached and their mucous membranes are inevitably damaged. This fracture type occurs in 14–24 % of patients [15, 16]; in 9 % of these cases, the fracture is unilateral and nondisplaced . Le Fort I fractures do not affect the orbit.
Maxillary fractures: (a, b) Le Fort I fracture. (c, d) Le Fort II fracture. (e, f) Le Fort III fracture (see explanation in the text) (Materials from www.aofoundation.org were used for this illustration)
Le Fort II (pyramidal) fractures are the most common type (55–64 %) of maxillary fractures. They result from a blow to the lower or mid-maxilla. Two variations are possible depending on the angle of trauma.
A direct blow results in a typical pyramidal fracture with or without injury to the hard palate. The fracture line crosses the nasofrontal suture and descends along the medial orbital wall (the lacrimal bone) and the orbital floor to reach the inferior orbital fissure where it turns forward. It crosses the infraorbital rim along the infraorbital foramen or in close proximity to it, extends along the anterior wall of the maxillary sinus above the zygomatic bone, and crosses the pterygomaxillary fissure to reach the pterygoid process of the sphenoidal bone. The nasal septum can be involved in bilateral fractures. The cribriform plate of the ethmoidal bone and the frontal sinus are damaged in more severe cases, and the pattern of the naso-orbito-ethmoidal fracture is formed (Fig. 7.2c, d). Thus, the maxillary and nasal bones are detached from the zygomatic and neurocranial bones in Le Fort II fractures (complete detachment of the maxilla and nasal bones).
A side blow gives rise to a unilateral zygomatico-orbital fracture combined with Le Fort I and/or II fractures .
Le Fort III fracture (also known as transverse fractures or craniofacial disjunction) results from a blow to the nasal dorsum or the upper third of the maxilla. The fracture line starts near the nasofrontal or frontomaxillary suture and extends posteriorly along the medial orbital wall through the lacrimal groove and the ethmoidal bone. Located posteriorly, the appreciably thick sphenoid bone usually (but not always) prevents the extension of the fracture line into the optic canal. Hence, the fracture turns toward the infraorbital fissure and extends posterolaterally through the lateral orbital wall, the frontozygomatic suture, and the zygomatic arch. It subsequently runs posteriorly and downward along the greater wing of the sphenoidal bone to reach the upper section of the pterygoid process and the body of the sphenoidal bone. In the nasal cavity, the fracture line runs through the base of the perpendicular plate of the ethmoidal bone and the vomer and between the pterygoid processes of the sphenoidal bone to its body (Fig. 7.2e, f). Thus, the facial bones are detached from the neurocranial bones in this type of fracture. Le Fort III fractures are observed in 8–12 % of patients with maxillary fractures [15, 16].
Although the practical significance of the Le Fort classification is obvious, one should bear in mind that it is not perfectly comprehensive. The reason is that the energy of the trauma sustained in motor vehicle accidents is much higher than that used by R. Le Fort in his experiments. In most cases, contemporary maxillary fractures are a combination of various Le Fort fractures (either I–II or II–III) (Fig. 7.6d) [18, 19]. The fracture lines frequently diverge from the trajectories described above to form unilateral (hemi-Le Fort) fractures, mixed fractures, and other atypical varieties of fractures . Finally, extremely high-energy maxillary fractures can be combined with injuries to the mandible and cranial vault, thus forming panfacial fractures.
Furthermore, the Le Fort classification does not describe the two rather common types of maxillary injuries. The first type is a small isolated fracture that usually localizes near the alveolar process of the anterior wall of the maxillary sinus or the nasomaxillary suture. This type of injury is caused by a strong local impact of an object (e.g., a hammer) (Fig. 7.6e, f). The rate of these fractures is as high as 9–10 % . The second type comprises fractures resulting from an impact directed upward and damaging the horizontal “reinforcing ribs” of the face: the alveolar process, the infraorbital rim, and the zygomatic arc.
7.3 Clinical Presentation of Maxillary Fractures
7.3.1 Clinical Presentation of Le Fort I Fractures
The patient’s general condition is usually fair. The main reasons for complaints are maxillary pain aggravated by biting and chewing, difficulty with biting off food using one’s front teeth, numbness in teeth and gingival mucous membrane, abnormal occlusion, foreign body sensation in the throat, and blocked nasal breathing.
Examination reveals soft tissue swelling of the upper lip and cheek as well as flattened nasolabial folds. Elongation of the lower third of the face that is sometimes observed indicates that there is a significant downward displacement of the maxillary fragment.
Inspection of the oral cavity usually reveals a hematoma along the upper gingivobuccal fold. The soft palate seems to be elongated; the palatine uvula contacts the posterior pharyngeal wall. Mobility of the alveolar process of the maxilla is revealed by palpation (Fig. 7.3).
7.3.2 Clinical Presentation of Le Fort II Fractures
Due to the concomitant brain injury, the overall patient status is from moderate to severe. In addition to the complaints listed above, conscious patients complain of numbness in the distribution of the infraorbital nerve; lack of olfactory ability or anosmia, indicating that the olfactory nerve fibers in cribriform plate orifices have been either disrupted or entrapped; and hemorrhage from the oral and nasal cavities (or lacrimal points if the nasolacrimal canal is damaged). Some patients also complain of diplopia.
Swelling of the periorbital tissues, the upper lip, and the nasal root causes typical alterations in facial configuration, which can change depending on patient’s body position. The patient’s face is flattened in the lying position as the fragment is displaced posteriorly. The face of a standing patient is elongated due to the downward displacement of the maxilla.
The clinical presentation also includes the “raccoon eyes” finding. The hematoma affects the lower eyelid, the medial canthus (spreading to the nasal root skin), and the medial portion of the upper eyelid. Chemosis and subconjunctival hemorrhage are rather frequent findings. Facial, cervical, and thoracic subcutaneous emphysema can also be observed.
The condition of the nasal and oral cavities is thoroughly assessed at the next stage.
Le Fort II fractures are characterized by mobile nasal bones. Examination of the nasal cavity allows one to identify fresh or old hematomas, nasal leak of CSF, and submucosal membrane hematoma of the nasal septum that is associated with a high risk of abscess and necrosis of the adjacent cartilage (Fig. 7.4b).
Examination of the oral cavity aims at evaluating the state and completeness of dental occlusion, stability of the hard palate, and condition of soft tissues. Intraoral palpation of the maxillary surface provides additional data on the condition of the nasomaxillary and zygomaticomaxillary buttresses and the anterior wall of the maxillary sinus.
Examination of the oral vestibule reveals mucous membrane hemorrhages near the molar and premolar teeth affecting the buccal mucosa. Open bite, caused by posterior and outward displacement of the maxilla and occlusion only at the level of molars, is quite typical (Fig. 7.5). Sensitivity of the gingival mucosa to pain is reduced near the incisors, canines, and premolars. As opposed to Le Fort I fracture, sensitivity of molar teeth and the corresponding gingival areas and the mucous membrane of the hard and soft palate is retained. Percussion of upper teeth results in cracked pot sound.
Symptoms of maxillary fractures: (a, b) mesial occlusion, facial elongation, enophthalmos (indicated by deepening of the upper eyelid groove shown with an arrow), and flattening of the zygomatic area. (c) The frontal view of a patient. (d) Hemi-Le Fort I fracture (Reproduced with permission of professor G.A. Khatskevich and associate professor M.M. Solovyev)
Protrusion of the lateral pharyngeal wall that is observed in some cases indicates that there is a hematoma in the peripharyngeal space.
The “bone step” finding is revealed by palpation of the infraorbital rim and the zygomaticoalveolar crest. This finding cannot be detected near the nasofrontal suture because of significant swelling of soft tissues. However, bony crepitus can be discovered here. To do so, the left index finger is placed on the infraorbital rim and the thumb is placed on the nasal root, while the maxilla is gently rocked in the anteroposterior direction with the right hand. Synchronous displacement of the bone fragment in both tested areas indicates that there is a fracture. When the supposed bone fragment is displaced up and down, the skin above the nasal root forms a fold or changes its color as its tension is altered (Fig. 7.3).
Pain is aggravated when pressing against the hooks of the pterygoid processes of the sphenoidal bone (Guérin’s sign). The bone fragment displaced downward moves upward, thus reducing the length of the midface and nose.
The physical evaluation of the eyes and the orbit includes the following: integrity of the orbital rims and walls, visual acuity and pupillary responses, muscle balance, eyeball position in the orbit, and the intercanthal distance.
Orbital pathological conditions are very diverse and can include:
Combination of symptoms typical of orbital floor fractures (vertical diplopia, eno- and hypoglobus, infraorbital neuropathy) [1, 25].
Combination of findings typical of a naso-orbito-ethmoidal fracture caused by dislocation of the central fragment and telescopic posterior displacement of the broken nasal bones. Optic neuropathy and CSF leak caused by fracture of the perpendicular plane of ethmoidal bone are associated with the highest risk.
7.3.3 Clinical Presentation of Le Fort III Fractures
The serious condition of a patient is often aggravated by basilar skull fracture, brain injury, and traumatic shock .
Conscious patients complain of diplopia when being in a vertical position, swallowing difficulties, foreign body sensation in the throat, feeling of choking and nausea, malocclusion, and inability to open the mouth properly due to the pressure exerted by the coronoid process of the mandible on the displaced zygomatic bone.
Profound soft tissue swelling makes the patient’s face moon shaped. While being flattened in a supine position, the face becomes elongated when the patient sits up, and the eyeballs are displaced downward, thus expanding the palpebral fissure and causing diplopia. During jaw closing, the eyeballs and the orbital floor are displaced upward.
It is usually difficult to evaluate the condition of facial bones by visual inspection because of the concomitant soft tissue swelling, ecchymosis, and continuous hemorrhage. Nevertheless, edema of periorbital tissues and facial flattening are indicative of extensive Le Fort III fracture.
The “bone step” sign and bony crepitus can hardly be detected by palpation of the tissues within the nasal root and the superior-outward edge of the orbit because of profound soft tissue swelling. Furthermore, the displaced fragments in patients with a high-energy fracture may seem immobile during palpation. Guérin’s sign is also observed.
A CSF leak is easily disguised by often bleeding from the mouth, nose, and ears in this type of fracture . Latent, intermittent CSF leak is identified by provocative tests including straining effort and compression of jugular veins, the test using double stains,1 the handkerchief test,2 and lumbar puncture (required to detect blood in CSF).
Ophthalmic symptoms and findings in Le Fort III fractures include the symptoms of all the fractures described in the previous chapters (inferomedial, NOE, and zygomatico-orbital ones). Severe enophthalmos and hypoglobus are observed in 90 % of cases.
There is a high risk of damaging the eyeball, the optic nerve, and structures in the superior orbital fissures (the oculomotor, trochlear, and abducent nerves), particularly in patients with the congenitally narrow superior orbital fissure. Reduced visual acuity is a sign of possible damage to the visual pathway. Other major factors also associated with high risk of injury to structures of the visual pathway are as follows: orbital floor fracture, comminuted facial fracture, diplopia, and amnesia. The acronym BAD ACT referring to blowout fracture, acuity, diplopia, amnesia, and comminuted trauma makes it easy to remember the high-risk factors of damage to the visual pathway .
Kiratli et al.  reported a case of luxation of the eyeball accompanied by rupture of the optic nerve and all extraocular muscles except for the medial rectus. Jellab et al.  reported two cases of eyeball displacement into the maxillary sinus. Tunçbilek and Işçi  reported midfacial trauma aggravated by traumatic enucleation.
The concomitant fracture of the petrous part of the temporal bone is accompanied by hearing impairment or loss, vestibular disorders, and facial nerve paralysis .
Hence, the full-scale clinical presentation of classical Le Fort II and III fractures with profound fragment displacement includes the following signs and symptoms:
Severe pain when closing the jaw, open bite
Facial elongation and flattening due to posterior and downward displacement of maxillary fragments
Pain during palpation of the pterygoid process of the sphenoidal bone
The “bone step” sign during palpation of the upper half of the lateral and mid-thirds of the infraorbital rim and the zygomaticoalveolar crest
Orbital and facial emphysema
Ocular dystopia and/or diplopia
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7.4 Radiological Diagnosis
The usefulness of plain X-rays is limited because of the shielding effect of swollen soft tissues and overlapping projections of numerous midfacial bones . Nevertheless, frontal and lateral radiography of the skull and targeted examination of the zygomatic bone are still used for screening.
X-rays of accessory nasal sinuses shed light on the condition of zygomatic arches, nasal bones, the anterior and lateral walls of the maxillary sinus, and the orbital rims. Radiography provides appreciably clear imaging of all maxillary buttresses. Lateral radiography of the skull allows one to evaluate the sagittal dimensions of the midface and the integrity of the anterior and posterior walls of the frontal sinus. Hemosinus, facial edema, and emphysema also have certain diagnostic values. Evaluation of the condition of the cervical spine makes it possible to rule out its injury (e.g., a whiplash fracture). However, CT scanning is an indispensable method for analyzing multiple fractures, evaluating the concomitant injuries to the cartilages and soft tissues, and revealing injuries involving the optic canal and remains the main diagnostic tool (Fig. 7.6).
Radiological signs of Le Fort II maxillary fractures: (a) a computed axial tomography (CAT) scan showing the fracture line of the anterior and lateral walls of the maxillary sinus (shown with arrows). (b) A coronal CT scan clearly visualizes the fracture of the lateral wall of the maxillary sinus. (c) 3D reconstruction of a pyramidal fracture (shown with arrows). (d) A combination of Le Fort I and II fractures (shown with arrows). (e, f) A blow-in fracture of the anterior wall of the maxillary sinus. (g) The fracture line of lateral orbital walls is seen in the CAT scan. (h, i) Sagittal (h) and coronal (i) CT scans clearly visualize the fracture of the body of the sphenoidal bone. (j) Axial CT scan of the fracture of greater wing of the sphenoidal bone. (k, l) Coronal (k) and sagittal (l) CT scans of the fracture of pterygoid process. (e–l) A blow-in fracture of the anterior wall of the maxillary sinus (shown with arrows) (Reproduced with permission of G.E. Trufanov and E.P. Burlachenko)
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